Study on the relationship between the structure and activities of alkyl methacrylate-maleic anhydride polymers as cold flow improvers in diesel fuels

In order to find efficient cold flow improvers for diesel fuels derived from crude oil, copolymers (R1MC-MA) were prepared making use of the copolymerization of methacrylate (R1MC) of various alkyls with maleic anhydride (MA), and terpolymers (R1MC-MA-R2MC) were prepared by the reaction of long-chain alkyl methacrylate (R1MC), maleic anhydride (MA), and short alkyl methacrylate (R2MC). The additives were purified and characterized by IR, 1H-NMR, and GPC. The activities of the synthetic products as the cold flow improvers in two diesel fuels were investigated. The results indicate that: (1) the alkyl chain length of R1 in R1MC-MA copolymers significantly affects the solid point depressing performance. When the long-chain alkyl R1 is n-C14H29- and the reaction material molar ratio (R1MC/MA) is 1:2, the C14MC-2MA possesses the best ΔSP property; (2) the (C14MC-MA-R2MC) terpolymers all demonstrate excellent solid point depression properties when the short-chain alkyl R2 varies from CH3- to n-C8H17-; (3) however, all of the tested copolymers and terpolymers do not demonstrate necessary cold filter plugging point depression performance.